<template>
    <div class="echart" ref="chartDom"></div>
</template>
<script setup>
//按需导入需要用到的 vue函数 和 echarts
import * as echarts from 'echarts'
import { ref, inject, onMounted, onBeforeUnmount, defineProps, watch } from "vue";
// const echarts = inject("echarts");
//获取 dom 和 父组件数据 并定义"myChart"用于初始化图表
const chartDom = ref(null)
let myChart = null;
const props = defineProps({
    option: Object,
})
//重绘图表函数
const resizeHandler = () => {
    myChart.resize();
}
//设置防抖，保证无论拖动窗口大小，只执行一次获取浏览器宽高的方法
const debounce = (fun, delay) => {
    let timer;
    return function () {
        if (timer) {
            clearTimeout(timer);
        }
        timer = setTimeout(() => {
            fun();
        }, delay);
    }
};
const cancalDebounce = debounce(resizeHandler, 500);
//页面成功渲染，开始绘制图表
onMounted(() => {
	//配置为 svg 形式，预防页面缩放而出现模糊问题；图表过于复杂时建议使用 Canvas
    myChart = echarts.init(chartDom.value,null, {renderer:'svg'})
    // myChart = echarts.init(chartDom.value)
    myChart.setOption(props.option, true);
    //自适应不同屏幕时改变图表尺寸
    window.addEventListener('resize', cancalDebounce);
})
//页面销毁前，销毁事件和实例
onBeforeUnmount(() => {
    window.removeEventListener('resize', cancalDebounce)
    myChart.dispose()
})
//监听图表数据时候变化，重新渲染图表
watch(() => props.option, () => {
    myChart.setOption(props.option, true);
}, { deep: true })

</script>
<style lang="scss" scoped>
.echart {
    width: 100%;
    height: 100%
}
</style>